Hematite nanoparticles have a broad range of outstanding applications such as in wastewater treatment, electrolytic studies, and photoelectrochemical and superparamagnetic applications. Therefore, ...the development of facile and novel methods to synthesize hematite nanoparticles using low-cost raw materials is an important and timely requirement. In this study, we have developed a facile economical route to synthesize hematite nanoparticles, directly from the naturally occurring material laterite. Laterite is a rock that is rich in Fe and Al with extensive distribution in large mineable quantities in many countries around the world, though not yet utilized for major industrial applications. In this method, ferric ions in the laterite were leached out using acid and the solution obtained was hydrolyzed with slow-release hydroxyl ions which were acquired by aqueous decomposition of urea. The resulted precursor was calcined to obtain hematite nanoparticles. Characterization data shows that the final product is comprised of spherical hematite nanoparticles with a narrow particle size
vs.
frequency distribution with an average particle diameter of 35 nm. The synthesized product has a purity of over 98%. Furthermore, the synthesized nanoparticles show an excellent adsorption percentage as high as 70%, even when the initial dye concentration in water is 5000 ppm and the amount of material is minimal, towards acid dyes which are excessively used in textile based industries. Such acid dyes are a threat to the environment when they are released into water bodies by industries in massive quantities. Therefore synthesized hematite nanoparticles are ideal to treat dye wastewater in industrial effluents because such nanoparticles are low cost and economical, and the synthesis procedure is rather facile and effective.
High purity hematite nanoparticles have been synthesized by a facile method using naturally occurring laterites for industrial dye effluent treatment applications.
While climate change is a global phenomenon, its negative impacts are more severely felt in poor countries because of their high dependence on natural resources and limited coping capacity to climate ...variability and extremes. However, investigation of the relationship between poverty, climate variability and water-related disasters is complex. This article investigates the relationship between disaster risk, poverty, and the associated vulnerability of households and communities. The case study on which the article is based was carried out in Sri Lanka, a developing country prone to disasters. Data collected from household surveys conducted in North Central province, Sri Lanka, was examined with the use of cross tabulation and regression analysis techniques. Our study is novel because it considers floods and droughts together and compares their economic impact on socioeconomic groups at a local level.
Our findings show that households depend heavily on natural resources for their livelihood, and that those with low income suffer greater losses from floods and droughts than households with high income. On the other hand flood impact is higher on households depend heavily on natural resources for their livelihood, and having lower income. The study uses survey data to examine the relationship between disaster frequency and localized poverty, an issue rarely considered in past literature. We show that low income households that depend fully on natural resources for their livelihood are exposed to more frequent disasters and most vulnerable to financial losses incurred through floods and droughts. To combat the effects of disasters, the Sri Lankan government might encourage members of poor households to seek at least some income from non-agricultural endeavors.
The uterine cervical length is an important risk factor for preterm birth. The aim of this study was to assess cervical length distribution in women with singleton pregnancies, measured by ...transvaginal ultrasound between 16 and 24 weeks, and its association with population characteristics.
We searched electronic databases and other sources for studies published from April 1, 1990 to July 21, 2020. Of the 2019 retrieved publications, full-text versions of 137 articles were considered. We included 77 original articles that reported cervical length measurements of 363,431 women. The main aim of this study was to identify the pattern of cervical length in different populations. We collected demographic and clinical data concerning the population, in addition to information regarding the ultrasound examination and cervical length measurement. Regarding study bias, 56 were at low risk of bias and 21 were at medium risk of bias.
The meta-analysis included 57 articles with data from 158,346 women. The mean cervical length was 37.96. mm (95% CI 36.68, 39.24). Cervical length was shorter in women from Africa and Asia, in those from low-income countries, with a lower body weight, and in those who delivered before 37 gestational weeks. We found that the cervical length from pooled studies is longer than that usually discussed in the literature. Regarding limitations, we had difficulty assessing our main variable because there was no consistent pattern in the way authors reported cervical length measurement. Another limitation was the great heterogeneity between studies.
The use of a single cutoff value to define a short cervix diagnosis, an important risk factor for preterm birth, may not be correct and cervical length must be considered according to maternal population characteristics. Future studies should identify different specific curves and cutoff values for cervical length in different populations. This meta-analysis was registered in the PROSPERO database under CRD42017070246 at https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=70246.
Floods cause severe damage to people as well as to properties. The same flood can cause different levels of damage to different households, but investigations into floods tend to be conducted on ...regional and national scales, thereby missing these local variations. It is therefore necessary to understand individual experiences of flood damage to implement effective flood management strategies on a local scale. The main objectives of this study were to develop a model that represents the relationship between socioeconomic conditions and flood damage at a local scale, and to understand the socioeconomic factors most closely tied to flood damage. The analysis is novel in that it considers not only the impact of flood characteristics, but also the impact of social, economic, and geographic factors on flood damage. This analysis derives from a quantitative modeling approach based on community responses, with the responses obtained through questionnaire surveys that consider four consecutive floods of differing severity. Path analysis was used to develop a model to represent the relationships between these factors. A randomly selected sample of 150 data points was used for model development, and nine random samples of 150 data points were used to validate the model. Results suggest that poor households, located in vulnerable, low‐lying areas near rivers, suffer the most from being exposed to frequent, severe floods. Further, the results show that the socioeconomic factors with the most significant bearing on flood damage are per capita income and geographic location of the household. The results can be represented as a cycle, showing that social, economic, geographic, and flood characteristics are interrelated in ways that influence flood damage. This empirical analysis highlights a need for local‐scale flood damage assessments, as offered in this article but seldom seen in other relevant literature. Our assessment was achieved by analyzing the impact of socioeconomic and geographic conditions and considering the relationship between flood characteristics and flood damage.
Abstract
The expansion and potential rupture of the swim bladder due to rapid decompression, a major cause of barotrauma injury in fish that pass through turbines and pumps, is generally assumed to ...be governed by Boyle’s Law. In this study, two swim bladder expansion models are presented and tested in silico. One based on the quasi-static Boyle’s Law, and a Modified Rayleigh Plesset Model (MRPM), which includes both inertial and pressure functions and was parametrised to be representative of a fish swim bladder. The two models were tested using a range of: (1) simulated and (2) empirically derived pressure profiles. Our results highlight a range of conditions where the Boyle’s Law model (BLM) is inappropriate for predicting swim bladder size in response to pressure change and that these conditions occur in situ, indicating that this is an applied and not just theoretical issue. Specifically, these conditions include any one, or any combination, of the following factors: (1) when rate of pressure change is anything but very slow compared to the resonant frequency of the swim bladder; (2) when the nadir pressure is near or at absolute zero; and (3) when a fish experiences liquid tensions (i.e. negative absolute pressures). Under each of these conditions, the MRPM is more appropriate tool for predicting swim bladder size in response to pressure change and hence it is a better model for quantifying barotrauma in fish.
Chronic stress is a major risk factor for several human disorders that affect modern societies. The brain is a key target of chronic stress. In fact, there is growing evidence indicating that ...exposure to stress affects learning and memory, decision making and emotional responses, and may even predispose for pathological processes, such as Alzheimer's disease and depression. Lipids are a major constituent of the brain and specifically signaling lipids have been shown to regulate brain function. Here, we used a mass spectrometry-based lipidomic approach to evaluate the impact of a chronic unpredictable stress (CUS) paradigm on the rat brain in a region-specific manner. We found that the prefrontal cortex (PFC) was the area with the highest degree of changes induced by chronic stress. Although the hippocampus presented relevant lipidomic changes, the amygdala and, to a greater extent, the cerebellum presented few lipid changes upon chronic stress exposure. The sphingolipid and phospholipid metabolism were profoundly affected, showing an increase in ceramide (Cer) and a decrease in sphingomyelin (SM) and dihydrosphingomyelin (dhSM) levels, and a decrease in phosphatidylethanolamine (PE) and ether phosphatidylcholine (PCe) and increase in lysophosphatidylethanolamine (LPE) levels, respectively. Furthermore, the fatty-acyl profile of phospholipids and diacylglycerol revealed that chronic stressed rats had higher 38 carbon(38C)-lipid levels in the hippocampus and reduced 36C-lipid levels in the PFC. Finally, lysophosphatidylcholine (LPC) levels in the PFC were found to be correlated with blood corticosterone (CORT) levels. In summary, lipidomic profiling of the effect of chronic stress allowed the identification of dysregulated lipid pathways, revealing putative targets for pharmacological intervention that may potentially be used to modulate stress-induced deficits.
The application of high-pressure coolant (HPC) in cutting processes can strongly influence the wear on the cutting tools providing a longer tool life. This is possible due to better penetration of ...the fluid into the tool–workpiece and tool–chip contact region, providing a better cooling effect and decreasing tool wear through lubrication of the contact areas. To better understand the effect on tool life, it is necessary to investigate wear mechanisms, as these depend on the frictional/thermal conditions at the tool–chip interface. The objective of this work is to study how tool wear mechanisms are influenced by cutting fluid applied at high pressure and in different concentrations in the turning operation of AISI 316 austenitic stainless steel using coated cemented carbide tools. The experiments were carried out in a turning operation and the cutting fluid was applied at different pressures (10, 15 and 20MPa) between the chip and tool at the rake face. The results are compared to dry cutting and wet cutting. Cemented carbide tools of class ISO K coated with TiN, Al2O3 and Ti (C,N), using the chemical vapor deposition at medium temperature technique (MTCVD), were employed. The main findings were the reduction of tool wear and reduced tool-chip contact length with the use of high-pressure coolant. The main wear mechanism observed on the rake face and the flank face was adhesion. The high-pressure coolant technique was more efficient than both overhead fluid applications and dry cutting with regard to the reduction of cutting tool wear. The lowest wear was obtained when the fluid was applied with a concentration of 10% and at a pressure of 10MPa.
Vogt-Koyanagi-Harada disease (VKHD) is a rare granulomatous inflammatory disease that affects pigmented structures, such as eye, inner ear, meninges, skin and hair. This disease is mainly a Th1 ...lymphocyte mediated aggression to melanocytes after a viral trigger in the presence of HLA-DRB1*0405 allele. The absence of ocular trauma or previous intraocular surgery sets VKHD appart from sympathetic ophthalmia, its main differential diagnosis. The disease has an acute onset of bilateral blurred vision with hyperemia preceded by flu-like symptoms. The acute uveitic stage is characterized by a diffuse choroiditis with serous retinal detachment and optic disc hyperemia and edema. Fluorescein angiography in this phase demonstrates multiple early hyperfluorescent points. After the acute uveitic stage, ocular and integumentary system pigmentary changes may appear. Ocular findings may be accompanied by lymphocytic meningitis, hearing impairment and/or tinnitus in a variable proportion of patients. Prompt diagnosis followed by early, aggressive and long-term treatment with high-dose corticosteroids is most often ensued by good visual outcomes. However, some patients may experience chronic uveal inflammation with functional eye deterioration. The current review discusses the general features of VKHD, including epidemiology, classification into categories, differential diagnosis and current therapeutic approaches.
Abstract Anthonomus grandis grandis (Coleoptera: Curculionidae) is a pest with a large potential for destruction in cotton crops, causing damage to the cotton reproductive structures. The earwig ...Marava arachidis (Dermaptera: Labiidae), is an important reference as a predator in several crops and being easy to rear in the laboratory. To analyze the potential biocontrol of M. arachidis of A. grandis grandis larvae, a study of predatory capacity was conducted using a functional response model. A. grandis grandis larvae were exposed to the predator at densities 1, 2, 4, 6, and 8 larvae (= prey/predator / Petri dish), with 30 replications at each density. Contact between the predator and the prey occurred for 24 hours; after this period, the level of predation of M. arachidis was assessed based on the proportion of preyed larvae. The linear logistic regression coefficient was used with a beta-binomial generalized linear model to determine the functional response. The negative signal of the linear coefficient and the goodness-of-fit tests revealed a quadratic or type II functional response, with the number of prey varying from 1.00 larva (density of 1 larva/predator) to 6.50 larvae (density of 8 larvae/predator). Therefore, the results of the present study demonstrate a high predatory capacity of M. arachidis on A. grandis grandis larvae.
Resumo Anthonomus grandis grandis (Coleoptera: Curculionidae) é uma praga com grande potencial de destruição nas lavouras de algodão, causando danos às estruturas reprodutivas do algodoeiro. A tesourinha Marava arachidis (Dermaptera: Labiidae), é uma importante referência como predador em diversas culturas agrícolas, além de ser de fácil criação em laboratório. Com o objetivo de analisar o potencial biocontrole de larvas de A. grandis grandis por M. arachidis, foi realizado um estudo de capacidade predatória utilizando um modelo de resposta funcional. Larvas de A. grandis grandis foram expostas ao predador nas densidades: 1, 2, 4, 6 e 8 larvas (= presa/predador/placa de Petri), com 30 repetições em cada densidade. O contato entre o predador e a presa ocorreu durante 24 horas; após esse período, o nível de predação de M. arachidis foi avaliado com base na proporção de larvas predadas. O coeficiente de regressão logística linear foi utilizado com um modelo linear generalizado beta-binomial para determinar a resposta funcional. O sinal negativo do coeficiente linear e os testes de ajuste revelaram uma resposta funcional quadrática ou tipo II, com o número de presas variando de 1,00 larva (densidade de 1 larva/predador) a 6,50 larvas (densidade de 8 larvas/predador). Portanto, os resultados do presente estudo demonstram uma alta capacidade predatória de M. arachidis sobre larvas de A. grandis grandis.
Tadpoles are diverse and abundant consumers, and knowledge of their feeding ecology and trophic status is essential in understanding their functional roles within aquatic habitats. Here we revisit ...Altig, Whiles, and Taylor (2007)'s paper, which highlighted the knowledge gaps in tadpole feeding ecology and the application of modern techniques, such as stable isotope and fatty acid analyses to better quantify dominant food resources, food assimilation, and the trophic status of tadpoles.
We reviewed the ecological studies that have been published since 2007 that used stable isotopes and fatty acid analyses, also metagenomics and ecological stoichiometry analyses. We describe the ecological roles of tadpoles in freshwater ecosystems and identify knowledge gaps regarding tadpole feeding ecology across biogeographic regions.
Worldwide declines in amphibian abundance and diversity create an urgent need to document their feeding ecology and trophic status. As consumers, tadpoles play important functional roles in nutrient cycling, energy flow, and bioturbation. They also exhibit context‐dependent trophic plasticity in response to abiotic and biotic gradients, which complicates understanding of their trophic roles.
Most studies of tadpole trophic ecology have been conducted primarily on species from the families Ranidae, Bufonidae, and Hylidae from Neotropic and Nearctic regions, while species in tropical regions such as Africa and Asia lack ecological information for tadpoles. There continues to be a need for studies of tadpole diets and/or trophic ecology in Africa and Southeast Asia regions where species endemism is threated by the growth of anthropogenic activities.
The majority of studies have focused on trophic ecology of tadpoles from the perspective of single species or at relatively small spatial and temporal scales. Studies that address questions from an ecosystem perspective were scarce, but are critical for conservation and management. Future research should aim to address the role of tadpoles as consumers across broader spatiotemporal scales.
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